High resolution recording medium and method for producing same

ABSTRACT

A recording medium with a multicolor high resolution pattern created by layer packs. Pattern-forming layers of the layer packs are successively applied by photolithographic means in a sequence corresponding to a color of the high resolution pattern. The pattern-forming layers of the layer packs are separate from one another on the substrate of the recording medium. 
     The process for producing the recording medium includes applying a photoresist layer to a substrate and developing the photoresist. Pattern-forming layers are successively applied over the whole surface of the substrate in a sequence corresponding to a color. The remaining photoresist and the layers overlying it are removed to leave a sequence of pattern-forming layers on the substrate separate from any adjacent pattern-forming layers.

BACKGROUND OF THE INVENTION

This invention relates to recording mediums displaying a high resolution multicolor pattern. These recording mediums are especially used in the formation of microtopographical maps.

The recording of multicolor images is described in U.S. Pat. No. 3,727,233. The recording medium disclosed in this patent is made by applying a metal layer of high reflectivity to a glass substrate and covering this metal layer with an organic polymer layer. The desired pattern is formed on the polymer layer by exposing it to electron beams. The irradiation intensity of the electron beams determines the pattern formed by the polymerization of the layer. Over the polymer layer, another metal layer of high reflectivity is applied. The interference patterns yield a multicolor image when viewed under natural light. One disadvantage of this method is that the metal layers are of equal thickness over the entire substrate, thereby permitting no variations in the saturation of the individual colors of the image. The patterned interference layer formed by the organic polymer is very heat sensitive. Because of this and the high elimination strength associated with this, strong reenlargement (Ruckvergrosserung) of the multicolor image is not permitted. The deficient lightfastness and shrinkage of the organic polymer interference layer over time can cause the colors to change.

The German unexamined patent specification No. OS 26 58 623 discloses a recording medium which records with high information density. This recording medium is particularly used for multicolor micro-images. At least two interference filters (Interferenzfilter) for two different colors are applied onto the substrate of this recording medium. Each of the interference filters is made with an unpatterned inorganic absorption-free interference layer which extends with equal thickness over the entire substrate. This inorganic interference layer is bounded on each side by at least one inorganic reflecting layer which forms the pattern of the recording. In another embodiment disclosed in this patent specification, the unpatterned interference layer is bounded on each surface by at least one patterned, high-refracting absorption-free layer. Between every two high-refracting layers there is present an unpatterned, low-refracting absorption-free layer. The presence of the unpatterned interference layers which extend with equal thickness over the entire substrate in the different embodiments of this patent specification, incurs the requirement that for each desired color a series of patterning steps is necessary. During this process the exposure mask must be adjusted for each patterning step, requiring the greatest of precision. The adjustment of the exposure mask is also very time consuming.

SUMMARY OF THE INVENTION

The present invention is directed to a recording medium for high resolution multicolor patterns made with patterned or pattern-forming layer packs. The pattern-forming layers of the layer packs are separate from one another on the substrate. The pattern-forming layers of a layer pack are applied successively to the substrate in a sequence corresponding to a color in the multicolor pattern. The layer packs include an interference filter and/or an edge filter (Kantenfilter). In recording mediums with interference filters, at least part of the interference layer is a pattern-forming layer in a layer pack.

It is an object of the present invention to reduce the number of process steps necessary in creating the recording. Several pattern-forming layers are successively applied over the whole surface of the substrate after a layer of photoresist has been developed. The pattern is formed for all of these layers at one time when the remaining photoresist is removed with all of the layers overlying it. A further object of the present invention is avoiding the problems of adjusting the exposure mask for multiple patterning steps, thereby improving the optical quality of the recorded pattern.

Advantageously, the present invention allows for production of a recording medium with great savings in time and cost. The method used to produce the recording medium is more accurate so that the rejection rate is considerably lower than in formerly used methods. In addition, the present invention achieves a better color hue purity and color hue saturation.

The invention itself, together with further objects and attendant advantages, will best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a-c are schematic diagrams of recording mediums of the present invention having metal dielectric interference filters;

FIGS. 2a and b are schematic diagrams of recording mediums of the present invention having purely dielectric interference filters (reindielektrischen Interferenzfiltern);

FIGS. 3a and b are schematic diagrams of recording mediums of the present invention having semi-filters (Halbfiltern);

FIGS. 4a-d are schematic diagrams of recording mediums of the present invention having induced transmission filters (induzierten Transmissionsfiltern);

FIGS. 5a and b are schematic diagrams of recording mediums of the present invention having edge filters (reflectors); and

FIGS. 6a and b are schematic diagrams of recording mediums of the present invention having edge filters and metal dielectric filters.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1a-c, there are shown recording mediums of the present invention using dielectric interference filters in the form of pattern-forming layer packs 1₁, 1₂ and 1₃ to create a first color and pattern forming layers packs 2₁, 2₂ and 2₃ to form a second color. The layer packs 1₁,2₁ are generated to form the recording medium of FIG. 1a as follows. A first photoresist layer (not shown) is applied to the whole surface of a substrate 3₁. This layer is exposed by means of a first exposure mask. After the first photoresist layer has been developed, an inorganic reflecting layer 4₁ is applied over the whole surface of the substrate 3₁. This is followed by the application of an inorganic absorption free interference layer 5₁ to the whole substrate surface. The optical thickness of the interference layer 5₁ defines the first color. The interference layer 5₁ is covered by an inorganic layer 6₁ over the whole surface of the substrate. The remaining first photoresist layer is removed together with the layers 4₁ -6₁ overlying the remaining photoresist layer. This leaves only the layer pack 1₁ on the substrate 3₁.

To generate a second color on the substrate 3₁, a second photoresist layer is applied over the whole surface. This is then exposed by means of a second exposure mask. After the second photoresist layer has been developed, an inorganic layer 7₁, an inorganic absorption-free interference layer 8₁ and an inorganic layer 9₁ are applied over the whole surface of the substrate 3₁. The interference layer 8₁ defines the second color hue. The remaining second photoresist layer together with the layers 7₁ -9₁ overlying it is removed. This leaves a second layer pack 2₁ locally separate and independent from the layer pack 1₁ on the substrate 3₁.

Another embodiment for recording mediums having dielectric interference filters of the present invention is shown in FIG. 1b. Here the first step in the process of generating the recording is to apply an inorganic reflecting layer 4₂ over the whole surface of the substrate 3₂. The inorganic reflecting layers are generally made of metal and are hereinafter referred to as metal layers. Then, to generate a first color hue, a first photoresist layer is applied over the surface. The first photoresist layer is exposed by means of a first exposure mask and the layer is developed. Then, over the whole surface of the substrate 3₂ an inorganic absorption-free interference layer 5₂ defining the first color hue is applied. Over this a metal layer 6₂ is placed. The remaining first photoresist layer together with the layers 5₂,6₂ present on top of it is removed. This leaves the layer pack 1₂ on the substrate 3₂. A second photoresist layer is applied over the whole surface of the substrate. This layer is exposed by means of a second exposure mask to form the pattern for the second color. After the second photoresist layer has been developed, an inorganic absorption-free interference layer 8₂ is applied over the whole surface of the substrate 3₂. A metal layer 9₂ is applied over the interference layer 8₂. The remainder of the second photoresist layer together with the layers 8₂,9₂ on top of it is removed to leave the layer 8₂, 9₂ separate from the layers 5₂, 6₂ on the substrate 3₂.

For still another embodiment of this recording medium reference is now made to FIG. 1c. A metal layer 4₃ is applied over the entire surface of the layer carrier 3₃. Over the metal layer 4₃, an inorganic absorption-free interference layer 5₃ for the generation of the first color is applied. This layer is subsequently covered by a first photoresist layer. The same steps as before are followed. The first photoresist layer is exposed and developed. The first layer pack 1₃ is completed by applying a metal layer 6₃ over the substrate 3₃, followed by the removal of the first photoresist layer with the metal layer 6₃ positioned over it. This leaves the layer pack 1₃ on the substrate 3₃. To generate the second color, a second photoresist layer is applied over the whole surface of the substrate 3₃ and this is exposed by means of a second exposure mask. After the second photoresist layer has been developed, an inorganic absorption-free interference layer 8₃ is applied over the whole surface of the substrate to complete the interference layer for the second layer pack. A metal layer 9₃ is then applied over the whole surface. Once again, the remainder of the second photoresist layer, together with the layers 8₃, 9₃ present on top of it, are removed. This leaves the layers 8₃, 9₃ and the layer 6₃ separated on the substrate 3₃.

In this embodiment just described for FIG. 1c, the interference layers 5₃ and 8₃ combine to define the second color. The metal layer 6₃ for layer pack 1₃ and the interference layer 8₃ and metal layer 9₃ for layer pack 2₃ are the pattern-forming layers in this embodiment. In FIG. 1b, the pattern-forming layers are the layers 5₂,6₂ in the layer pack 1₂ and the layers 8₂,9₂ in the layer pack 2₂. In FIG. 1a, the pattern-forming layers are the layers 4₁,5₁,6₁ in layer pack 1₁ and the layers 7₁,8₁,9₁ in the layer pack 2₁. The sequence of the pattern-forming layers in each of the layer packs 1, 2 correspond to the color displayed by the respective layer pack. The metal layers 4,6,7,9 are partially permeable layers.

The present invention may also be made of recording mediums having purely dielectric interference filters. Referring now to FIGS. 2a and b, layer packs 11₁,11₂ form the pattern for a first color and pattern-forming layer packs 12₁,12₂ produce a second color.

The first step in generating the recording medium of FIG. 2a is to apply over the entire surface of the substrate 13₁, a first photoresist layer. The photoresist layer is exposed using a first exposure mask. After the photoresist layer has been developed, the following layers are successively applied to the entire surface of the substrate 13₁ in the following sequence corresponding to the first color: a high-refracting absorption-free layer 14₁, a low-refracting absorption-free layer 15₁, a high-refracting absorption-free layer 16₁, an inorganic absorption-free interference layer 17₁ to define the first color, a high-refracting absorption-free layer 18₁, a low-refracting absorption-free layer 19₁ and a high-refracting absorption-free layer 20. The remaining first photoresist layer, together with the layers 14₁ -20₁ present over it, is then removed. This leaves the layer pack 11₁ on the substrate 13₁. The second color is generated in the same manner. A second photoresist layer is applied over the whole surface of the substrate 13₁. This is exposed by means of a second exposure mask. After this second photoresist layer has been developed, the pattern-forming layers for the second layer pack 12₁ are applied over the whole surface of the substrate. The layers as applied in succession include a high-refracting absorption-free layer 21₁, a low-refracting absorption-free layer 22₁, a high-refracting absorption-free layer 23₁, an inorganic absorption-free interference layer 24₁ defining the second color, a high-refracting absorption-free layer 25₁, a low-refracting absorption-free layer 26₁ and a high-refracting absorption-free layer 27₁. As usual, the remainder of the second photoresist layer, together with the layers 21₁ -27₁ lying over it, is then removed. This leaves the layer packs 12₁ and 11₁ independent from one another on the substrate 13₁.

Another embodiment of the present invention using the purely dielectric interference filters is shown in FIG. 2b. Over the entire surface of the substrate 13₂ are applied the whole-surface layers including a high-refracting absorption-free layer 14₂, a low-refracting absorption-free layer 15₂ and a high-refracting absorption-free layer 16₂. The substrate 13₂ is then covered with the first photoresist layer for the generation of the first color. The photoresist layer is exposed and developed using a first exposure mask. This is followed by applying an inorganic absorption-free interference layer 17₂ over the whole surface of the substrate 13₂ to define the first color. The remaining layers are successively applied over the surface of the substrate 13₂ in a sequence corresponding to the first color. In order, these layers include a high-refracting absorption-free layer 18₂, a low-refracting absorption-free layer 19₂ and a high-refracting absorption-free layer 20₂. The remaining first photoresist layer is removed together with the layers 17₂ -20₂ overlying it. The layer pack 11₂ is left remaining on the substrate 13₂. To generate the second layer pack 12₂, a second photoresist layer is applied over the whole surface of the substrate 13₂. This layer is exposed by means of a second exposure mask. After it has been developed the pattern-forming layers of the layer pack 12₂ are applied in succession, including an interference layer 24₂ defining the second color, a high-refracting absorption-free layer 25₂, a low-refracting absorption-free layer 26₂ and a high-refracting absorption free layer 27₂. The remainder of the second photoresist layer together with the layers 24₂ -27₂ lying over it is then removed.

In FIG. 2a, the pattern-forming layers of the layer pack 11₁ are the layers 14₁ -20₁ and for the layer pack 12₁ are the layers 21₁ -27₁. In FIG. 2b, the pattern-forming layers are layers 17₂ -20₂ in the layer pack 11₂ and layers 24₂ -27₂ in the layer pack 12₂. The pattern-forming layers of each layer pack are separate from each other on the substrate.

The present invention may also be made with semifilters as shown in FIGS. 3a and b. Pattern-forming layer pack 31₁ on the substrate 33₁ in FIG. 3a is made of a high-refracting absorption-free layer 34₁, a low-refracting absorption-free layer 35₁, a high-refracting absorption-free layer 36₁, an inorganic interference layer 37₁ defining the first color and a metal layer 38₁. The layers 34₁ -38₁ are the pattern-forming layers of the layer pack 31₁. Pattern-forming layer pack 32₁ on the substrate 33₁ is made of a high-refracting absorption-free layer 39₁, a low-refracting absorption-free layer 40₁, a high-refracting absorption-free layer 41₁, an inorganic absorption-free interference layer 42₁ defining the second color and a metal layer 43₁. The layers 39₁ -43₁ are the pattern-forming layers of the layer pack 32₁.

Referring now to FIG. 3b, the layer pack 31₂ on the substrate 33₂ consists of a high-refracting absorption-free layer 34₂ covering the whole surface, a low-refracting absorption-free layer 35₂ also covering the whole surface, a high-refracting absorption-free layer 36₂, an inorganic absorption-free interference layer 37₂ defining the first color and a metal layer 38₂. The pattern-forming layers of the layer pack 31₂ are the layers 36₂ -38₂. The layers 34₂ and 35₂ cover the whole surface and do not contribute to the pattern formation. The layer pack 32₂ on the substrate 33₂ consists of the whole surface layers 34₂ and 35₂, a high-refracting absorption-free layer 41₂, an inorganic absorption-free layer 42₂ defining the second color and a metal layer 43₂. The pattern-forming layers of the layer pack 32₂ are the layers 41₂ -43₂. The recording mediums of FIGS. 3a and b are generated by photolithographic means as described for the preceding embodiments. The metal layers 38 and 43 are partially permeable layers.

Referring now to FIGS. 4a-d, recording mediums of the present invention are shown using induced transmission filters. In FIG. 4a, the pattern-forming layer pack 51₁ on the substrate 53₁ consists of the following layers in succession: a high-refracting absorption-free layer 54₁, a low-refracting absorption-free layer 55₁, a high-refracting absorption-free layer 56₁, a first inorganic absorption-free interference layer 57₁ in accordance with the first color, a metal layer 58₁, a second inorganic absorption-free interference layer in accordance with the first color, a high-refracting absorption-free layer 60₁, a low-refracting absorption-free layer 61₁ and a high-refracting absorption-free layer 62₁. This sequence of layers corresponds to the first color. The layers 54₁ -62₁ are the pattern-forming layers of the layer pack 51₁. Pattern-forming layer pack 52₁ on the substrate 53₁ consists of a similar arrangement of layers in succession: a high-refracting absorption-free layer 63₁, a low-refracting absorption-free layer 64₁, a high-refracting absorption-free layer 65₁, a first inorganic absorption-free interference layer 66₁ in accordance with the second color, a metal layer 67₁, a second inorganic absorption-free interference layer 68₁ in accordance with the second color, a high-refracting absorption-free layer 69₁, a low-refracting absorption-free layer 70₁ and a high-refracting absorption-free layer 71₁. The layers 63₁ -71₁ are the pattern-forming layers of the layer pack 52₁.

Referring now to FIG. 4b, the layer pack 51₂ on the substrate 53₂ consists of a whole-surface high-refracting absorption-free layer 54₂, a whole-surface low-refracting absorption-free layer 55₂, a whole surface high-refracting absorption-free layer 56₂, a first inorganic absorption-free interference layer 57₂ corresponding to the first color, a metal layer 58₂, a second inorganic absorption-free interference layer 59₂ corresponding to the first color, a high-refracting absorption-free layer 60₂, a low-refracting absorption-free layer 61₂ and a high-refracting absorption-free layer 62₂. The layers 57₂ -62₂ are the pattern-forming layers of the layer pack 51₂, while the whole surface layers 54₂ -56₂ do not contribute at all to the pattern formation. The layer pack 52₂ on the substrate 53₂ consists of a similar arrangement of layers in succession including, the whole surface layers 54₂ -56₂, a first inorganic absorption-free interference layer 66₂ corresponding to the second color, a metal layer 67₂, a second inorganic absorption-free interference layer 68₂ corresponding to the second color, a high-refracting absorption-free layer 69₂, a low-refracting absorption-free layer 70₂ and a high-refracting absorption-free layer 71₂. The layers 66₂ -71₂ are the pattern-forming layers of the layer pack 52₂ while the whole-surface layers 54₂ -56₂ are non-pattern-forming layers which do not contribute to the pattern formation. The recording mediums according to the FIGS. 4a and b are generated by photolithographic means as described for the previous embodiments.

Referring now to FIG. 4c, the process for generating the recording medium there shown shall be described. A first photoresist layer is applied over the whole surface of the substrate 53₃. This layer is exposed by means of a first exposure mask. After the photoresist layer has been developed, the following layers are applied over the whole surface of the substrate 53₃ in succession in a sequence which corresponds to the desired first color, a high-refracting absorption-free layer 54₃, a low-refracting absorption-free layer 55₃, a high-refracting absorption-free layer 56₃, a first inorganic absorption-free interference layer 57₃ corresponding to the first color, a metal layer 58₃ and a second inorganic absorption-free interference layer corresponding to the first color. The remaining first photoresist layer, together with the layers 54₃ -59₃ which are situated over the remaining photoresist, are removed. To generate the second color on the substrate 53₃, a second photoresist layer is applied over the whole surface. This is exposed by means of a second exposure mask. After the second photoresist layer has been developed, the whole surface of the substrate 53₃ is covered by the following layers in succession, a high-refracting absorption-free layer 63₃, a low-refracting absorption-free layer 64₃ , a high-refracting absorption-free layer 65₃, a first inorganic absorption-free interference layer 66₃ in accordance with the second color, a metal layer 67₃ and a second inorganic absorption-free interference layer 68₃ in accordance with the second color. The remaining second photoresist layer, together with the layers 63₃ -68₃ lying over it, is then removed. Left remaining on the substrate 53₃ are the pattern-forming layers 54₃ -59₃ of the first layer pack 51₃ and the pattern-forming layers 63₃ -68₃ of the layer pack 52₃ for the second color. The layer packs and the substrate are now covered with a high-refracting absorption-free layer 60₃, a low-refracting absorption-free layer 61₃, and high-refracting absorption-free layer 62₃. These whole-surface layers 60₃ -62₃ are non-pattern-forming layers which do not contribute to the pattern formation.

Another method for carrying out the present invention results in the recording medium shown in FIG. 4d. A first photoresist layer is applied over the whole surface of the substrate 53₄ and is exposed by means of a first exposure mask. After the layer has been developed, the following layers are successively applied over the whole surface of the substrate 53₄ in a sequence corresponding to the first color: a high-refracting absorption-free layer 55₄, a low-refracting absorption-free layer 55₄, a high-refracting absorption-free layer 56₄ and a first inorganic absorption-free interference layer 57₄ corresponding to the first color. The remaining first photoresist layer, together with the layers 54₄ -57₄ lying over it, are then removed. To generate the second color, a second photoresist layer is applied over the whole surface of the substrate 53₄. The second photoresist layer is exposed by means of a second exposure mask. After it has been developed, the whole surface of the substrate 53₄ is covered by a high-refracting absorption-free layer 63₄, a low-refracting absorption-free layer 64₄, a high-refracting absorption-free layer 65₄ and a first inorganic absorption-free layer 65₄ according to the second color. The remaining second photoresist layer, together with the layers 63₄ -66₄ situated on top of it, is then removed. At this point, remaining on the substrate 53₄ are the first part of the layer pack 51₄ for the first color and the first part of the layer pack 52₄ for the second color. A metal layer 58₄ is applied over the entire surface of the substrate 53₄ and does not contribute to the pattern formation. A third photoresist layer is applied over this layer and is exposed by means of the first exposure mask. After developing the third photoresist layer, the whole surface of the substrate 53₄ is covered by the successive application of the following layers in sequence for producing the first color: a second inorganic absorption-free interference layer 59₄ corresponding to the first color, a high-refracting absorption-free layer 60₄, a low-refracting absorption-free layer 61₄ and a high-refracting absorption-free layer 62₄. The remaining third photoresist layer, together with the layers 59₄ -62₄ lying over it, is then removed. For generating the second color, a fourth photoresist layer is applied over the entire surface of the substrate 53₄ and this is exposed by means of a second exposure mask. After the fourth photoresist layer has been developed, the following layers are applied in succession over the whole surface of the substrate 53₄, a second inorganic absorption-free interference layer 68₄, corresponding to the second color, a high-refracting absorption-free layer 69₄, a low-refracting absorption-free layer 70₄ and a high-refracting absorption-free layer 71₄. The remaining fourth photoresist layer, together with the layers 68₄ -71₄ lying over it, is then removed. The metal layers 58,67 found in FIG. 4a-d are partially permeable layers.

It is also possible to use edge filters in the recording mediums of the present invention as shown in FIGS. 5a and b. A pattern-forming layer pack 81₁ on the substrate 83₁ of FIG. 5a consists of two edge filters 84₁ -88₁ and 89₁ -93₁ lying one over the other. In each edge filter the low-refracting absorption-free layers 85₁,87₁, and 90₁,92₂ are bounded on both sides by the high-refracting absorption-free layers 84₁, 86₁, 88₁, and 89₁,91₁,93₁. The layer pack 82₁ on the substrate 83₁ also consists of two edge filters 94₁ -98₁ and 99₁ -103₁ lying one over the other. Each edge filter consists of high-refracting absorption-free layers 94₁, 96₁, 98₁, 99₁, 101₁, 103₁ between which there are present low-refracting absorption-free layers 95₁,97₁,100₁,102₁. The layers 84₁ -93₁ are the pattern-forming layers of the layer pack 81₁ and the layers 94₁ -103₁ are the pattern-forming layers of the layer pack 82₁.

Referring now to FIG. 5b, the layer pack 81₂ on the substrate 83₂ consists of two edge filters 84₂ -88₂ and 89₂ -93₂ lying one on the other. The edge filter 84₂ -88₂ consists of whole surface absorption-free layers 84₂,86₂,88₂, between which there are present whole surface low-refracting absorption-free layers 85₂,87₂. The edge filter 89₂ -93₂ consists of the high-refracting absorption-free layers 89₂,91₂,93₂, between which there are present low-refracting absorption-free layers 90₂, 92₂. The layers of the edge filter 90₂ -93₂ are the pattern-forming layers of the layer pack 81₂. The layer pack 82₂ on the substrate 83₂ consists of the whole-surface edge filter 84₂ -88₂ over which is present the edge filter 99₂ -103₂. This edge filter 99₂ -103₂ consists of high-refracting absorption-free layers 99₂, 101₂, 103₂ between which are present the low-refracting absorption-free layers 100.sub. 2, 102₂. The layers of the edge filter 99₂ -103₂ are the pattern-forming layers of the layer pack 82₂. The whole surface edge filter 84₂ -88₂ does not contribute to the pattern formation of the layer packs 81₂,82₂.

In the filters 1,2,11,12,31,32,51,52 the first and second color hues are determined by the optical thicknesses of the interference layers 5,8,17,24,37,42, 57,59,66,68. The saturation of these color hues is determined by the reflection capacity of the metal layers 4,6,7,9,38,43,58,67 and respectively of the high-refracting layers 14,16,18,20,21,23,25,27,34,36,39,41, 54,56,60,62,63,65,69,71 and of the low-refracting layers 15,19,22,26,35,40,55,61,64,70. Thus, the layers and their sequence in a layer pack will determine the optical qualities of the resulting color.

In an edge filter (reflector), the spectrum of high transmission declines over a steep slope to a spectrum range of low transmission. The optical thicknesses of the high-refracting and low-refracting layers of an edge filter amount to a quarter wavelength (λ/4), where the wavelength (λ) is equal to the greatest wavelength of the least transmission by the edge filter. In FIG. 5a, the edge filters of the first part of the layer packs 84₁ -88₁,94₁ -98₁ display in the range of the two color hues to be generated, a transmission which increases as the wavelength increases. The other edge filters in the second part of the layer packs 89₁ -93₁,99₁ -103₁ display in this range a decreasing transmission as wavelength increases. By the superposition of the edge filters 84₁ -88₁,94₁ -98₁ with the edge filters 89₁ -93₁,99₁ -103₁ there is achieved a maximum transmission for the desired color hues.

At a certain ratio of layer thickness of the edge filters to the size of the spacing between layer packs in the high resolution pattern, difficulties may arise in the removal of the remaining photoresist layer together with the overlying layers. It is preferred, therefore, to form the filters according to FIG. 5b. The lower edge filter 84₂ -88₂ covers the whole surface. The whole-surface edge filter 84₂ -88₂ must in certain wavelength ranges have as high and as constant a transmission as possible. This is achieved by a variation of the optical thicknesses of the high-refracting and low-refracting layers 84₂ -88₂. Preferably, the optical thicknesses remaining within the range of ±10% from the amount of a quarter wavelength (λ/4), as defined above.

The layer packs may be made as a combination of different filters. Referring now to FIGS. 6a and b, there is shown recording mediums having edge filters and superimposed metal dielectric filters. The layer pack 111₁ on the substrate 113₁ in FIG. 6a, consists of an edge filter 114₁ -118₁ with high-refracting absorption-free layers 114₁,116₁,118₁ between which there are present low-refracting absorption-free layers 115₁ and 117₁. Layer pack 111₁ also includes a metal dielectric interference filter 119₁ -121₁, with an interference layer 120₁ which is bounded on both sides by inorganic reflecting layers 119₁,121₁. The layer pack 112₁ on the substrate 113₁ consists of an edge filter 122₁ -128₁ with high-refracting absorption-free layers 122₁,124₁, 126₁,128₁ between which are low-refracting absorption-free layers 123₁,125₁,127₁. Also included in layer pack 112₁ is a metal dielectric interference filter 129₁ -131₁ having an interference layer 130₁ which is bounded on both sides by inorganic reflecting layers 129₁,131₁. The layers 114₁ -121₁ are the pattern-forming layers of the layer pack 111₁, and the layers 122₁ -131₁ are the pattern-forming layers of the layer pack 112₁.

Referring now to FIG. 6b, the layer pack 111₂ on the substrate 113₂ consists of an edge filter 114₂ -118₂ which covers the whole surface. This edge filter 114₂ -118₂ includes whole-surface high-refracting absorption-free layers 114₂,116₂,118₂ between which there are present whole-surface low-refracting absorption-free layers 115₂,117₂. The layer pack 111₂ also includes a metal dielectric interference filter 119₂ -121₂ having an interference layer 120₂ which is bounded on both sides by inorganic reflecting layers 119₂,121₂. It is the layers of the metal dielectric interference filter 119₂ -121₂ which are the pattern-forming layers of the layer pack 111₂. The layer pack 112₂ on the substrate 113₂ consists of the whole surface layers 114₂ -118₂, a low-refracting absorption-free layer 127₂, a high-refracting absorption-free layer 128₂ and a metal dielectric interference filter 129₂ -131₂. The metal dielectric interference filter 129₂ -131₂ includes an interference layer 130₂ which is bounded on both sides by inorganic reflecting layers 129₂,131₂. The layers 127₂,128₂ and the metal dielectric interference filter 129₂ -131₂ are the pattern-forming layers of the layer pack 112₂.

The inorganic reflecting layers 4,6,7,9,38, 43,58,67,119,121,129,131 are preferably made of silver, chromium, gold or aluminum or some combination of these materials. The interference layers 5,8,17,24,37,42,57, 59,66,68,120,130 are preferably made of MgF₂, SiO₂, Al₂ O₃, Fe₂ O₃ or some mixture of these materials. The high-refracting layers 14,16,18,20,21,23,25,27,34,36, 39,41,54,56,60,62,63,65,69,71,84,86,88,89,91,93,94,96, 98,99,101,103,114,116,118,122,124,126,128 are preferably made of TiO₂, ZrO₂, HfO₂, Nd₂ O₃ or some mixture of these materials. The low-refracting layers 15,19,22,26,35, 40,55,61,64,70,85,87,90,92,95,97,100,102,115,117,123, 125,127 are preferably made of MgF₂, SiO₂, Al₂ O₃, Fe₂ O₃ or some mixture of these materials. The substrate 3,13, 33,53,83,113 may be made of a transparent material or of an opaque material with a reflecting surface.

The layer packs 1,2,11,12,31,32,51,52,81,82,111, 112 and the pattern-forming layers making up the layer packs are applied successively by photolithographic means. The pattern-forming layers of the layer packs are applied in a sequence to correspond with the color of the layer pack in the high resolution pattern being formed. According to the process of the present invention, the pattern for a plurality of pattern-forming layers in a layer pack is formed simultaneously when the remainder of a developed layer of photoresist is removed along with the layers overlying it. In addition to the photolithographic process described above, it is possible for the layer packs to be generated by means of wet chemical etching processes or physical etching processes such as ion beam etching, sputter etching, plasma etching or reactive ion etching. It is also possible to generate the layer packs or pattern-forming layers of the layer packs by means of a vapor treatment mask or by means of a controlled particle jet, for example an electron or an ion jet.

Several different embodiments of the present invention may be employed on the same substrate. It is possible that on one part of a substrate, layer packs with partially whole-surface layers can be used while on other parts of the substrate layer packs without any whole-surface layers may be employed. It would also be possible to use different production processes on the same substrate. Different layer packs which are generated adjacent one another define a boundary zone between them which identifies the separation between the layer packs.

The recording mediums of the present invention provide the important advantages of improved color hue purity and color hue saturation. There is also a reduction in the number of rejects created using the present methods described above. These recording mediums are ideally suited for the recording of multicolor microtopographical maps.

Of course, it should be understood that various changes and modifications to the preferred embodiments described above will be apparent to those skilled in the art. For example, application of the layers can be carried out by a number of different methods including vaporization, sputtering, ion plating and precipitation from the vapor phase. It is therefore intended that such changes and modifications be covered by the following claims. 

We claim:
 1. In a recording medium for a multicolor high resolution pattern, said medium having a substrate which supports at least two pattern-forming layer packs, each comprising a filter such that each layer pack defines a respective color, the improvement comprising:at least one of said layer packs comprising at least an interference filter having a pattern forming interference layer patterned in the pattern of the interference filter of the respective one of the layer packs, said pattern forming interference layer extending over only a part of the substrate, only in a region defined by the pattern of the interference filter; at least the pattern forming layers of a first filter included in a first one of the layer packs being applied to the substrate locally separated from and prior in time to the pattern forming layers of a second filter included in a second one of the layer packs.
 2. The recording medium of claim 1 wherein at least one of said layer packs comprises at least one purely dielectric interference filter.
 3. The recording medium of claim 1 wherein at least one of said layer packs comprises at least one semifilter.
 4. The recording medium of claim 1 wherein at least one of said layer packs comprises at least one induced transmission filter.
 5. The recording medium of claim 1 wherein at least one of said layer packs comprises at least one metal dielectric interference filter.
 6. The recording medium of claim 1 wherein at least one of said layer packs comprises different filters arranged one over the other.
 7. The recording medium of claim 1 wherein at least one of said layer packs comprises at least one whole-surface layer applied on said substrate and at least one pattern forming layer.
 8. The recording medium of claim 7 wherein said at least one whole-surface layer comprises at least a part of at least one of the filters of the layer packs.
 9. The recording medium of claim 1 wherein the pattern forming layers of the first filter comprise a plurality of separate layers physically adjacent to and superimposed over one another, each shaped in a pattern corresponding to that of the first filter.
 10. The recording medium of claim 9 wherein the plurality of superimposed layers comprises the pattern forming interference layer.
 11. The recording medium of claim 1 wherein the pattern forming layers of the first filter comprise all of the layers of the first filter.
 12. The recording medium of claim 1 wherein at least one of the layer packs comprises at least an edge filter.
 13. The recording medium of claim 1 wherein said at least one of the layer packs comprising at least an interference filter further comprises an edge filter.
 14. In a recording medium for a multicolor high resolution pattern having a substrate which supports at least two pattern-forming layer packs, each comprising a filter, such that each layer pack defines a respective color, the improvement comprising:at least one of said layer packs comprising at least an edge filter; at least the pattern forming layers of a first filter included in a first one of the layer packs being applied to the substrate locally separated from and prior in time to the pattern forming layers of a second filter included in a second one of the layer packs.
 15. The recording medium of claim 14 wherein said at least one edge filter comprises a plurality of layers, each having an optical thickness which differs from a quarter wavelength (λ/4), where the wavelength is equal to the greatest wavelength of the least transmission by the edge filter.
 16. The recording medium of claim 15 wherein the optical thickness of the layers of the edge filter is within the range of ±10% of said quarter wavelength.
 17. The recording medium of claim 14 wherein the pattern forming layers of the first filter comprise a plurality of separate layers physically adjacent to and superimposed over one another, each shaped in a pattern corresponding to that of the first filter.
 18. The recording medium of claim 14 wherein the pattern forming layers of the first filter comprise all of the layers of the first filter. 